Since a conventional top-gate oxide TFT has lower parasitic capacitance and better electrical characteristics, it is regarded as the preferred backplate for organic light emitting display panel with large size and high resolution.
The TFT manufactured by top-gate self-alignment technology is commonly a coplanar structure, that is, the oxide active layer is disposed under all the metal layers (including the gate, the source and drain). However, the processes of manufacturing the same are more, the process time is long, and the cost is high.